Discussion on the Application of Stainless Steel

1. Application of stainless steel in construction industry

In recent years, the application of stainless steel as a building material is becoming increasingly widespread. The use of a wide range of reasons has a wide range of reasons, including a better understanding of the material, trying to update some of the design, imagine the production of a durable and no maintenance of structural materials.

In the early days, the use of stainless steel for construction was limited to certain occasions, where architects were looking for a new material with special effects in the absence of proper material in the past. In fact, many such occasions, stainless steel has been used for a long time and its effect has been a long period of continuous erosion of the role of stainless steel, so that manufacturers believe that stainless steel materials for outdoor applications even in high corrosive gases under the conditions of corrosion.

Because stainless steel is durable and almost no need to maintain the surface of these two characteristics, to make people more than ever before more attention to its application. Most of the price of building materials in a certain proportion of rapid rise, and there are many materials prices and far more than stainless steel. The cost of maintaining and maintaining the structure of the building inside and outside is even more soaring. Today’s architects must seriously consider the whole situation of the building. If the building needs to be replaced or repaired for many years, then the architect’s design is a failure.

In recent years, the walls of the swimming pool have been made of stainless steel. The main materials used for a long time need to be repaired and painted annually, especially in the northern region. The use of carbon steel and coated swimming pools also requires a large area of scrubbing and brushing each year, both of which add to the pool Considerable use of expenses. When the pool is made of stainless steel (304, 2B finish) to do the side wall, scrub is very simple, just water and soap can be quickly washed. Now the swimming pool is often used stainless steel tank wall and mixed soil bottom, the bottom of the concrete is mainly for non-slip.

Some buildings of the wall with 304, 8 mirror polished stainless steel as a material. The interconnected stainless steel plates are polished and colored to polish the walls with consistent color wither and reflective properties. In order to prevent grease, a large area of stainless steel plate exposed part (velvet feet) installed in the galvanized sheet and the compression plate composed of thick sandwich. Polished stainless steel plate with epoxy resin as binder and galvanized steel plate connected fixed.

Made of dry stainless steel can be very soft performance, so that it may be used as a roof cover material. It is because this material is easy to shape, durable and beautiful, so many architects choose stainless steel not only as a protective layer, but as an integral part of the overall design.

Some buildings (indoor skating rinks) are made of stainless steel in the construction of the roof of the Yongping overlapping layer, not only to make the building from the design point of view nice, but also because of the reflective surface of stainless steel, so that the indoor ice season to extend the rabbit Bear unreasonable investment.

For some special structures, often due to the application of stainless steel to make many problems resolved. For example, there is a garage, the design requirements of the parking garage on the parked vehicles not only have a protective effect and the exhaust gas has a good ventilation; but also to a certain degree of sunlight into the garage, the selection is durable and no maintenance. To meet the above requirements, the designer selected 6 * 10in (15 * 25cm) 201 stainless steel grating, the grid will be fixed on the vertical column, so that the internal and external staggered caused by overlapping layout.To enhance the effect of building facilities, staggered outer grid On the use of floating surface finish, the outer row of column grid using ordinary 2B finish, all inside the grid are 2D light exposure. This change in the pattern of the garage has a vivid appearance.

For a building roof structure, its life and appearance should be the same attention. At the airport’s restaurant, in order to make the roof beautiful, exhaust fans are covered with stainless steel plate. In the choice of cover material, but also stressed the non-reflective material. The selected materials are 304 stainless steel, rough polishing, low reflectivity, 6 finish. For the selection of light to pay special attention to the special due to the issue of glare, to prevent the pilot to reach the destination landing when the line of sight.

Office buildings inside and outside the building to the structure are used in stainless steel. Its architectural measures use stainless steel as a curtain wall. The columns at the entrance of the building are covered with stainless steel plates, and all the windows of the building are cleaned with stainless steel.

The ceilings above the office building lounge are made of stainless steel plates with relief. Use the male and female mold to punch the embossed part on the stainless steel sheet.

Stainless steel is not only long life, but also the production of captive convex to the structure of a good material, which can enhance the shape of the building beauty, it is often the main sign of the square.

Another example of stainless steel as a main material for outdoor end architecture is the famous arch that stands on the river.

Stainless steel material can be arbitrarily selected. It has a variety of different strength-to-weight ratios to suit all types of building structural requirements. In addition, different grades of surface finish also provide a range of options for a variety of different construction facilities to meet the actual needs. The architect’s bold idea will make the application of stainless steel in the construction industry increasingly widespread.

2. Application of stainless steel in marine installations

A variety of different types of stainless steel are increasingly widely and successfully used in a variety of marine environments. It must be pointed out that the long-term corrosion of stainless steel in seawater requires complex anti-corrosion engineering technology and substantial investment. Austenitic and martensitic stainless steels have long been used for superheater pipelines and turbine blades on navigational power units. It is not easy to maintain a low chloride content in these devices because there is no difference between the application of navigational power plants and the basic principles of general power generation devices. Stainless steel is also being used for large-capacity chemical containers on ocean-going merchant ships, and its use is in some respects different from the use of terrestrial chemical plants.

Most stainless steel grades are satisfactory in marine applications, but different grades are sensitive to stress corrosion cracking. Model 401 as the representative of the martensitic steel and 430 as the representative of the ferrite steel, in the ocean conditions, within a few months will rust. This uniform rust can be removed by mechanical grinding. The more popular stainless steel is austenitic stainless steel because of its strong resistance to corrosion (except for stress corrosion cracking). With the passage of time, austenitic stainless steel will also be black. This blackening can also be removed by grinding due to aesthetic or other reasons. Stainless steel in the water rarely produce uniform rust candle, so in actual use can not worry.

Propeller

Marine tugs and other vessels on the propeller can be made of cast stainless steel CF-8 (quite dry 304 stainless steel). When the vessel is not sailing, from the propeller spindle through the bearing to the hull, constitute a conductive metal circuit. Equivalent to 410 stainless steel casting propeller is also often used, and in other areas are widely used, such as for icebreakers and so on.

The development of modern stainless steel technology, has begun to use compound phase austenitic – ferritic stainless steel 20Cr-8Ni-3.5Mo to cast large-scale thrust vessel (weighing 3000kg).

Often working in the port of the vessel, particularly vulnerable to the surface of the logs or other floating body to accelerate the damage of the propeller. Therefore, the use of austenitic stainless steel propeller can be straightened or welded by the way to be repaired, which is a matter worthy of attention on the selection.

Pump

It has long been observed that the centrifugal pump in the sea under the conditions of work, such as the use of stainless steel components, can show a certain degree of reliability. In the flow of water, the use of CF-8M casting stainless steel impeller (its composition is equivalent to 316 stainless steel) and 316 stainless steel as the spindle, can not any problem. When the pump stops working, crevice corrosion and point corrosion is likely to be a serious problem. However, if you use a more lively and rusty cast iron to make a considerable wall thickness of the pump box, the cast iron in the downtime can play a cathodic protection. When the pump work, the cast iron box under the protection of the cathode will be able to make the next rust steel, but the flow of water to be cathodic protection. In addition, long-term work of the pump may be due to the use of alternating, both when the water replaced with fresh water and play a protective role.

Bulk containers

Stainless steel has been used as a bag container for shipping in liquefied natural gas (LNG), chemicals, beverages and so on. Cargo in the LNG container used to use 304L stainless steel, its purpose is not to corrosion-resistant but taking into account the mechanical properties at low temperatures.

For marine chemical containers, the purpose of using stainless steel is mainly to take into account its corrosion resistance, which is different from the storage and transportation of land chemicals. If the vessel belongs to a general irregular ship, the container carrying the chemical may also transport any item from acetic acid, bad pulp to xylene. Generally use 316L stainless steel for valves, cargo pumps, tubes, heating coils and containers themselves. The container may be made of integral stainless steel or coated with a carbon steel sheet with a 0.06 to 0.08 in. (1.5 to 2.0 mm) stainless steel plate. Before use, must be carefully checked whether the sheet is defective and thorough cleaning and passivation treatment.

Experiments show that the equipment with chemicals allowed to rinse with seawater, but then bored with fresh water quickly. For any stainless steel heating device in the container, do not start to prevent stress corrosion cracking until the chloride has not been thoroughly washed off. The design of the chemical container shall not be taken into account for the risk of crevice corrosion due to the presence of seawater. If the design scheme is not intended to contain water, it is necessary to consider a cathodic protection system to control the development of crevice corrosion. In this case, the stainless steel container may produce difficult to remove the calcareous deposits, which is a matter worthy of attention.

Heat exchanger

Forced water cycle system cooler and power station steam condenser has been widely used austenitic stainless steel pipe, the latter of the inlet due to high pollution and should not use copper alloy material. The more popular material is 316 stainless steel. In the coastal and harbor areas, a large number of foreign agglomerates and sludge into the condenser ducts are particularly vulnerable to serious obstacles, which must be taken to eliminate them. A reasonable measure is to use the rubber ball through the pipeline, because the rubber ball can produce squeeze to clean up the pipe wall. When the flow rate of seawater is about 1m / s, it can prevent the marine organic debris from being inhaled, so as to protect the condenser from corrosion. Unlike other non-ferrous alloys, pipes made of stainless steel as the condenser are not subject to the maximum flow rate, but are related to the economic effect of the entire pump unit.

Shaped ring

Series-type electrical connectors and related O-ring positioning devices are widely used 304 and 316 stainless steel manufacturing, especially marine and military engineering. Using the above materials can be satisfied with the use of results. O-shaped seals can be cathodic protected by hull, aluminum or other factors. If there is no cathodic protection, the O-ring is very bad (some in a few weeks) will produce cracks and corns and cause serious failure.

3. Oil extraction, mining industry

In recent years, oil extraction gradually from the land to the sea, offshore oil fields are more and more, and because the sea environment is relatively poor, the general pipe fittings can not meet their requirements. The superior performance of stainless steel pipe can meet the requirements of offshore oil field.

Source: China Pipe Fittings Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)

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